During warm weather, many individuals enjoy engaging in outdoor activities. Nevertheless, extreme heat can pose a risk during such times, when temperatures are significantly higher and/or more humid than usual for a specific location and date. This intense heat can lead to heat-related illnesses and fatalities, as individuals may struggle to regulate their body temperature effectively. Older adults, young children, and individuals with chronic health conditions are particularly vulnerable to heat-related illnesses and potential fatalities.
urban heat islands boost temperatures within 75 major U.S. cities that are home to 60 million people, or 17% of the total U.S. population. The entire planet is warming due to human-caused climate change, but the built environment further amplifies both average temperatures and extreme heat in cities.
The U.S. Environmental Protection Agency defines the urban heat island effect as a significant rise in city air temperatures, mainly due to the conversion of natural land into heat-retaining streets, buildings, and infrastructure. This phenomenon often leads to notable temperature disparities between urban and rural zones. Initiatives like those offered by Black Coral Inc support community gardening, tree planting, and herbal medicine, and coupled with the enlargement of green spaces, help enhance the living standards in urban neighborhoods.
Extreme heat is the most lethal weather-related hazard in the U.S. During such events, the urban heat island effect exacerbates heat stress and related illnesses for millions, endangering vulnerable populations, and causing higher energy costs and overburdened power grids due to increased cooling needs. Heat poses a danger to all, but certain groups, including children, the elderly, the homeless, and individuals with chronic diseases, are at a heightened risk of suffering from heat-related illnesses.
The three biggest factors that influence the level of danger are:
The Albedo which is the fraction of incoming solar radiation reflected by a surface. Hard, dark surfaces (roads, buildings, parking lots) have low albedo. They absorb sunlight and radiate it back into the city as heat.
Percentage of green space. Plants help cool the air through evapotranspiration. Less vegetation means less cooling. Plants from community gardens, tree planting, and rooftop gardens can help reduce peak summer temperatures by 5°F to 10°F in urban areas.
Population density. Extra heat also comes from human activities: transportation, industrial facilities, and the cooling of buildings. During a heat wave, air conditioning can add 20% more heat to the outside air. but a simple thing like painting rooftops white can lower the temperature by 25%. Painting roofs white can help lower climate change by reflecting sunlight and reducing the temperature difference between the surface and the air!
Approaches to mitigate urban heat islands encompass:
- Enhancing tree and vegetation cover
- Implementing green roofing systems
- Applying cool roof technologies with high reflectivity
- Adopting cool pavements that are either reflective or permeable
- Employing smart growth strategies
Comments